Commercially available laminate flooring (using high or medium density fiberboard or particle board as the core layer) has gained overwhelming success in the flooring market. The growth rate of the laminate flooring has remained in the double digits since the product was introduced in the United States market. The success of this product is credited to certain properties such as stain resistance, wear resistance, fire resistance, good cleanability, and the ability to use just about any type of printed design. In addition, the overall emission of organic compound vapor is low and the laminate flooring is considered color stable and environmentally friendly over other competing flooring products.
The biggest concern with commercially available laminate flooring is the moisture resistance of the finished product and the sensitivity of the raw materials (high or medium density fiberboard, paper, and particle board) to moisture during the manufacturing process. In some instances, the moisture can lead to some serious quality control issues and application restraints. For instance, and just to name a few, the higher moisture content in the product, such as in the particle board or fiberboard, can cause blistering and adhesion failure of the melamine surface to the core. Also, higher moisture contents can lead to dimensional instability of the finished product, which then results in the cupping or doming of the product, which is extremely undesirable, especially when installers are laying down the flooring. Also, excessive moisture contents can create edge peaking due to the swelling of the product and such edge peaking can result in edge chip-off or premature wear-out or can soil more quickly. The susceptibility to moisture content also leads to some installers not wishing to place such laminate flooring in areas which are subject to having water on the surface of the floor, such as in the kitchen and bathroom areas.
The suppliers of such laminate flooring have appreciated the problems associated with their products and have attempted to overcome these problems by developing laminate flooring having better moisture resistance by using melamine, phenolic, or isocyanate binders to partially replace urea resins present in the laminate flooring. While this improvement has made the product more moisture resistant, the current commercially available laminate floorings are still prone to moisture damage. For instance, the thickness swelling of laminate flooring can increase by 10% and water absorbency can exceed more than 15% according to the 24 hours water absorption test. Another attempted solution at the moisture resistance weaknesses of current laminate flooring has led some manufactures to apply a water-repellant material on the upper edges of the tongue and groove areas which.further serve to resist any moisture penetration through joints. Still another attempted solution involves applying silicone caulk to seal the edges and voids of the laminate perimeter where the laminate flooring meets the wall. However, if very stringent installation instructions are not followed, the laminate flooring will still be subjected to moisture damage.
Accordingly, there is a need to develop a laminate flooring system which overcomes the above weaknesses and disadvantages of current commercially available laminate flooring.
A feature of the present invention is to provide a laminate plank which can be used in a surface covering system which provides improved moisture resistance and is not susceptible to damage caused by moisture.
Another feature of the present invention is to provide a laminate plank and surface covering system which is economically feasible and permits easy installation and flexibility.
A further feature of the present invention is to provide a flooring system that improves foot comfort and other ergonomic benefits.
An additional feature of the present invention is to provide a surface covering system having improved sound deadening and other reduced sound transmission benefits.
Still another feature of the present invention is to provide a surface covering system which has significant improvements with respect to ease of installation and includes a fool-proof installation design and technique.
Another feature of the present invention is to provide a surface covering system which avoids the use of a wet adhesive application method.
Another feature of the present invention is to provide a flooring system that has great flexibility so as to make various shapes, sizes, and bevel edges.
Another feature of the present invention is to provide a flooring system that can alleviate the requirement of installing the plank in a given orientation.
Also, a feature of the present invention is provide a surface covering system which has the ability to tolerate some imperfections in the sub-floor or substrate and thus avoid telegraphing the imperfections on the surface covering itself.
A further feature of the present invention is to provide a surface covering system which has improved damaged resistance properties, such as improved impact strength and the like.
Additional features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. The features and other advantages of the present invention will be realized and attained by means of the elements and combinations particularly pointed out in the written description and appended claims.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, the present invention relates to a thermoplastic laminate plank, wherein the laminate plank has a core comprising at least one thermoplastic material, wherein the core has a top surface and a bottom surface. Optionally affixed to the top surface of the core can be a print layer, wherein the print layer has a top surface and a bottom surface. Also, an overlay layer is affixed to the top surface of the print layer. The plank can optionally contain an underlay layer located and affixed between the bottom surface of the print layer and the top surface of the core.
The present invention further relates to a method of making a thermoplastic laminate plank and involves the step of extruding at least one thermoplastic material into the shape of a core and optionally affixing a laminate on the core, wherein the laminate comprises an overlay layer affixed to the top surface of a print layer and optionally an underlay layer affixed to the bottom surface of the print layer.
Also, the present invention relates to a method of making a thermoplastic plank by printing a design directly on the top surface of the plank using any number of printing techniques, such as gravure printing, transfer printing, digital printing, Flexo printing, and the like. The method includes applying a protective coating on top of the printed design, such as a polyurethane type coating with or without wear resistant particles in the coating.
A further embodiment of the present invention relates to making a thermoplastic plank for flooring by co-extrusion techniques, which involves extruding at least one thermoplastic material into the shape of the core and also extruding a layer containing at least one thermoplastic material with one or more pigmented compounds on top of the extruded core, wherein the layer simulates a design, such as wood grain.
The present invention also relates to thermoplastic planks having the above-described characteristics.
It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the present invention, as claimed.